@Marianne *******
You’re absolutely right, Marianne — technically, any kind of work done while physically in Thailand does require the appropriate visa and work permit under Thai law.
What I’ve found (and what visa agents and expats confirm) is that in practice, many people quietly teach or freelance online — especially if:
• Their clients are outside Thailand
• Income goes to a foreign bank account
• They don’t advertise or take Thai clients
It’s not legal, but it’s also not aggressively enforced right now for small-scale online work. That said, the DTV visa looks like a great long-term option for those of us who want to be fully compliant and still work remotely.